Mars Express Blog

Mars Express Blog http://webservices.esa.int/blog/blog/7 Mars Express is Europe’s first planetary mission. At launch, the mission consisted of an orbiter carrying seven instruments for remote sensing observations of the planet, and a lander (Beagle 2) for on-the-spot measurements of Martian rock and soil. Mars Express started science observations at the Red Planet in January 2004, and since then it has been delivering an incredible amount of scientific results. The ‘Express’ part of the name highlights the fact that the spacecraft was built more quickly than any other comparable planetary mission. In fact, it took only five years from mission approval to launch. In addition to global studies of the surface, subsurface and atmosphere of Mars with unprecedented spatial and spectral resolution, the unifying theme of the Mars Express mission from orbit is the search for water in its various states, everywhere on the planet by all its seven instruments using different techniques. danielscuka 2013-02-11T11:41:04Z Tracking tiny slices of time: Phobos blocks Mars Express signal http://webservices.esa.int/blog/post/7/1387 On 30 April, in a carefully planned data-gathering exercise, ESA's Mars Express team used the passage of Phobos between Earth and the spacecraft to record precisely when a radio signal was blocked. The data may now lead to the best-ever determination of Phobos's orbit, knowledge that will help scientists better understand our planetary neighbour and its double-moon system. You'll recall our earlier posting, when we described MEX team plans to take advantage of a rare alignment of Earth - Phobos - Mars Express to measure precisely when the bulk of Phobos would block radio communications between the spacecraft and ESA's 35m Cebreros station in Spain. The prediction was that the 'occultation' would last around 12 seconds, from 21:21:22.9 to 21:21:34.1 UTC (spacecraft time). The predicted ground receive time was between 21:29:13.0 and 21:29:24.2 UTC (i.e. 7:50 mins later on Earth). The activity took place as planned on Monday, 30 April. Based on a reconstruction of the MEX orbit by ESA's Flight Dynamics team at ESOC, results indicate that the expected start time of the occultation by Phobos was 0.5 seconds earlier than that predicted. Similarly, the end time is 0.4 seconds earlier than predicted. The plot below indicates the actual situation as measured very precisely from Cebreros station.   <a id="res_21136" href="http://webservices.esa.int/blog/gallery/7/phobos_occultation_mars_express-2012.png"></a> <div style="text-align: center"> <a id="res_21136" href="http://webservices.esa.int/blog/gallery/7/phobos_occultation_mars_express-2012.png"><img src="http://webservices.esa.int/blog/gallery/7/previews-med/phobos_occultation_mars_express-2012.gif" border="0" /></a> </div>     It shows the view from Earth of the 'expected' occultation of the MEX signal by Phobos. The large, grey-green circle corresponds to the moon's disk; it is shown (at this scale) as a circle having a radius of 13.4 km. So why was the actual recorded occultation times a few seconds shorter than expected? ESA's Trevor Morley, lead flight dynamics specialist for Mars Express, says there are two possible reasons: <ol> <li>The best fit ellipsoid for the shape of Phobos has semi-axes of 13.4 x 11.2 x 9.2 km. The dashed circle shown in the plot has a radius of 9.2 km. The occultation duration depended upon the length of the chord across the real face of Phobos between the entry and exit points. The actual profile of Phobos needs to be applied to calculate this length (which is why photos/observations of Phobos are so important - Ed).</li> <li>A shorter than expected occultation duration would also occur if the present error in our prediction of Phobos's orbit is such that the moon's true position at the time was further towards the south.</li> </ol> Trevor says that the recorded timing data will now be shared with the MEX science team as well as with colleagues at NASA JPL; it is expected that they will be able to use these results to improve models of the Phobos orbit: “The Phobos orbit model that we are presently using was generated by Bob Jacobson of JPL and is almost certainly the most accurate one available. We will provide Bob with all the signal data plus our determined orbit of MEX,” he added. “Of course we can provide the data to any scientists working on this topic, including those who have been using directional data derived from Phobos images made by the MEX camera for the same purpose.” Mars Express Spacecraft Operations Manager Michel Denis says: <blockquote> It's part of the scientific method to make use of every opportunity to investigate our natural world. Also, it's second nature and ‘pride of craft’ for the mission operators to figure out how to achieve more with the same resources– whether that’s a spacecraft or a ground station. In this case, we could also achieve ‘extra science’ through tight cooperation between several teams here at ESOC – flight dynamics, ground segment, flight controllers – and we were able to fine-tune, second-by-second, an already packed science and communication plan. The team here have really done a nice job! </blockquote> General Science Operations Phobos 2012-05-04T11:56:29Z danielscuka An elegant solution - update in ESA web http://webservices.esa.int/blog/post/7/1383 A quick link and extract from an update on Wednesday in ESA's Science directorate web pages; it provides a nice overview of the 'return to science' situation. References to our very own VMC camera activities highlighted - and note very nice comments on teamwork! Click link to read the full report. <blockquote> While full science operations have now been resumed, a number of tasks remain to be completed. Most important among these is the implementation of an OBCP scheduler. This will enable the spacecraft to operate autonomously for up to a week, compared to the few days that are possible with the current FAST system. Work is also in hand to resume operation of the Visual Monitoring Camera (<a href="http://webservices.esa.int/blog/index.php?blogId=6" target="_blank">VMC – the 'Mars webcam'</a>). Enormous team effort Completely redesigning the way in which Mars Express is controlled has involved an enormous amount of work for the mission control team at the European Space Operations Centre (ESOC), assisted by their counterparts at the European Space Astronomy Centre (ESAC), PI-teams, other ESA experts and partners in industry. Everyone involved with the mission is extremely grateful for their hard work. Although the 'Express' in Mars Express highlights that the mission was developed in a short time and with a relatively modest budget, the ability to resume full operations after a very serious failure shows that the resulting design is both robust and flexible. Mars Express has now been restored to full operational capability and its potential mission lifetime remains unchanged </blockquote> <a href="http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=50026" target="_blank" title="An elegant solution">Full report via ESA Science & Technology</a> General Science Operations Recovery 2012-02-16T10:10:13Z danielscuka Skill, inspiration and teamwork: deep-space problem solving http://webservices.esa.int/blog/post/7/1382   "Hang on, lads; I've got a great idea..." <a href="http://en.wikiquote.org/wiki/The_Italian_Job_(1969_film)" target="_blank" title="Italian Job (Movie) 1969">The Italian Job, 1969 </a> <hr />   Last month, we spoke with several of the Mars Express team here at ESOC about their almost completed activities to restore, reconfigure and return Mars Express to service. An interview with Mars Express Spacecraft Operations Engineer Daniel Lakey   <hr /> <a id="res_21121" href="http://webservices.esa.int/blog/gallery/7/Daniel%20Lakey%20and%20the%20SSMM.png"> </a> <div style="text-align: center"> <a id="res_21121" href="http://webservices.esa.int/blog/gallery/7/Daniel%20Lakey%20and%20the%20SSMM.png"> <img src="http://webservices.esa.int/blog/gallery/7/Daniel_Lakey-with_SSMM.png" /> </a> </div> Spacecraft Operations Engineer Daniel Lakey sitting beside the SSMM A black box, edge-length 30 cm, is at the centre of the recent trouble with Mars Express. Daniel Lakey, an engineer working on the mission at ESOC in Darmstadt, looks down at the engineering model of said black box sitting on his desk and recalls the seemingly endless night shifts he has had to pull because of its twin mounted on Mars Express, orbiting the Red Planet many millions of kilometres away. In mid-August 2011, Mars Express unexpectedly placed itself into safe mode – think blue screen of death and reboot on a PC – because something went wrong either with the Solid-State Mass Memory (SSMM) housed inside this black box or with the on-board channels it uses to pass data to the spacecraft’s data management system (DMS) computer. To extend the PC analogy, imagine that the memory chips in your computer, the RAM chips, or the memory controllers that tell them what to do, suffered a fault. The memory might continue functioning, apparently normal, but whenever an electronic signal tried to access the faulty unit, the operation would fail and the system would crash. That's what happened with Mars Express. Holiday phone call at 3 AM "I was on holidays in England when I got the call at three o'clock in the morning. Since I'm assigned as the mission's software coordinator, the problem fell in my area of responsibility," says Lakey. Switching into safe mode means that the spacecraft automatically turns its solar panels to the Sun for maximum energy and its antenna to Earth for good communication – ostensibly very helpful in any untoward situation – but this process uses a significant amount  of vital fuel. Every unnecessary safe mode reduces the life of this hugely valuable mission, and in safe mode, normal gathering of scientific data stops. <a id="res_21119" href="http://webservices.esa.int/blog/gallery/7/ssmm_problem.png"><img src="http://webservices.esa.int/blog/gallery/7/21128-ssmm_problem.png" border="1" hspace="5" vspace="5" align="right" /></a>After an initial investigation, it was found that the safe modes were being triggered by the DMS computer whenever a batch  of commands transferred from the SSMM was interrupted. The problem: Big command batches were being interrupted, triggering a fuel-gobbling safe mode   The SSMM is a large-capacity device, and it stores large numbers of commands sent by mission controllers and the instrument scientists, as well as raw data gathered by the instruments (prior to their being radioed back to Earth). The SSMM then delivers a constant ‘stream’ of commands to the DMS computer one at a time; when the stream was interrupted – either due to a fault in the SSMM or due to some unknown problem with the on-board communication channels – the DMS detects the problem and auto-commands the spacecraft to switch to safe mode. Taking action - but problems persist At first, the flight control team executed the standard recovery procedures and restarted observations, hoping that Mars Express would function normally again. But, frustratingly, safe modes happened two more times in the next few weeks, even though the engineers had tried switching on-board systems to use back-up communication channels (there is only one SSMM), among many other normal fixes. Nothing in the routine procedures, it seemed, could prevent the frustrating safe modes from occurring. "We had to find a solution," says Lakey, "otherwise the mission would have soon been over." By late August, the team had already gone through many night shifts trying to coax the recalcitrant spacecraft into some sort of stable configuration, with little luck. "But then one day, an idea came to mind – while I was standing under the shower," says Lakey, with a laugh. "It occurred to me that, since something was happening to interrupt the flow of commands, triggering the safe mode, the solution might lie in by-passing the checks between the SSSM and the DMS computer, and finding a safe way to ignore problems with the link between the two." With a little checking, Lakey was able to determine that the problem was, in fact, an issue of 'transient communication problems' between the SSMM and the computer. "When the main computer sees this interruption, it interprets it as a serious problem and stops executing its 'To-Do' list of commands – because it doesn't know whether the list is complete," says Lakey. Fortunately, there's another, back-up, memory inside the DMS computer that could store the command stack, but it's much, much smaller than the SSMM, holding only 117 commands vs. over 3000. So the engineers set about reconfiguring the spacecraft's systems to transfer commands from the SSMM to the onboard computer's memory in a different way. Rather than a constant stream of commands, one at a time, the commands would be transferred as a discrete block of commands relating to one complete spacecraft activity, just before that activity started. "I thought we could use a trick, by packing the commands into smaller stacks and telling the on-board software to act only when it received a complete package. This 'all-or-nothing' scheme means we're no longer affected by the SSMM problems, but now we have more limits on what we can schedule in one go – but that's been proven to be acceptable." But would they buy it? As soon as he could, Lakey presented the idea to his colleagues. <img src="http://webservices.esa.int/blog/gallery/7/21129-ssmm_solution.png" border="1" hspace="6" vspace="5" align="left" />"Perhaps predictably, they reacted with an operations engineer's traditional caution and scepticism. The first answers were, 'No, no, that won't work, No way...' But, after a lot of discussion, they slowly came around to 'Oh wait... maybe we should look at this... it could work'," Lakey tells.   The solution: make command batches small With a clear consensus and the approval of Mars Express Spacecraft Operations Manager Michel Denis, the team set to work designing operations procedures that could be implemented using reduced command stacks, working first on just a certain set of basic on-board activities. This was a huge challenge. As designed, Mars Express normally makes use of thousands of commands; for example, it takes up to 50 separate commands to simply take a single photo of Mars using the HRSC camera. Using the new, reduced command stacks would prove worthless if engineers couldn't actually do anything with the reduced command stacks. Thus, making the solution work entails a massive amount of reprogramming to drastically reduce the number of commands needed to do anything on board. This work is what has kept the mission operations team on extended hours since November 2011. Smiles all around But, to everyone's delight, the solution is working and the team is substantially finished the work of  converting thousands of commands to on-board procedures to be  used much more efficiently than its designers had ever envisaged. "We are confident that all the Mars Express instruments and systems can be commanded using the reduced command stacks," says Lakey. "Now, we only need a few commands to capture an image and we can switch on and operate all the instruments at one time," he explains. "We can proudly say that Mars Express is working properly again – and, with luck – the fuel left could last for another ten years."   Science Operations Recovery 2012-02-08T16:31:28Z danielscuka Orcus Patera on Mars: What's in the crater? http://webservices.esa.int/blog/post/7/1379 A nice New Year's post starting the year with a question (and answer!) on the fabulous high resolution stereo camera (HRSC) image of Orcus Patera, first published by ESA (<a href="http://www.esa.int/esaSC/SEMDV9BO3DG_index_0.html" target="_blank">here</a>) in 2010, and reposted as the <a href="http://www.marstravel.org/2011/12/mars-photo-of-day-dec-31-2011.html" target="_blank">Image of the Day on 31 December 2011 at the Mars Travel blog</a>. Best wishes to everyone for a healthy and successful 2012. Details below! -- Daniel First, here's the image (click image to access the original post in ESA web):   <div style="text-align: center"> <a href="http://www.esa.int/esaSC/SEMDV9BO3DG_index_0.html" target="_blank" title="Original image via ESA web"><img src="http://webservices.esa.int/blog/gallery/7/472-20103007-2216-2238-6-co-01-OrcusPatera_300.jpg" border="1" alt="Orcus Patera is an enigmatic elliptical depression located between the volcanoes of Elysium Mons and Olympus Mons. This well-defined depression extends approximately 380 km by 140 km in a NNE–SSW direction. It has a rim that rises up to 1800 m above the surrounding plains, while the floor of the depression lies 400–600 m below the surroundings. The term ‘patera’ is used for deep, complex or irregularly shaped volcanic craters such as the Hadriaca Patera and Tyrrhena Patera at the north-eastern margin of the Hellas impact basin. However, despite its name and the fact that it is positioned near volcanoes, the actual origin of Orcus Patera remains unclear.Credits: ESA/DLR/FU Berlin (G. Neukum)" align="middle" /></a> </div>   <a href="http://download.esa.int/images/marsexpress/472-20103007-2216-2238-6-co-01-OrcusPatera_H1.jpg" target="_blank">Click for hi-res version </a> Orcus Patera is an enigmatic elliptical depression near Mars’s equator, in the eastern hemisphere of the planet. Located between the volcanoes of Elysium Mons and Olympus Mons, its formation remains a mystery. Often overlooked, this well-defined depression extends approximately 380 km by 140 km in a NNE–SSW direction. It has a rim that rises up to 1800 m above the surrounding plains, while the floor of the depression lies 400–600 m below the surroundings. Earlier today, Mars Travel blogger David Geaney sent in a question:  <blockquote> If you look at one of the central craters in Orcus Patera using the HRSC image, you will see there is something blue in the crater. What is the blue material? Thank you for your time and patience. </blockquote> We passed the query to Mars Express project scientist Olivier Witasse, who wrote: Hi David, The blue is not a lake.... It's dust, which emits in the blue part of the spectrum. In the data processing, the blue part is somewhat enhanced, which sometimes creates a wrong impression. Cheers, --Olivier     General Science 2012-01-02T14:30:46Z danielscuka MARSIS completes measurement campaign over Martian North Pole http://webservices.esa.int/blog/post/7/1378 <a id="res_21113" href="http://webservices.esa.int/blog/gallery/7/MARSIS2800_H_saup_410.jpg"><img src="http://webservices.esa.int/blog/gallery/7/previews/MARSIS2800_H_saup_410.gif" border="0" alt="Mars Express in orbit around Mars with the MARSIS antennae unfurled Date: 09 Dec 2011 Satellite: Mars Express Copyright: ESA This artist's illustration depicts Mars Express in orbit around Mars with the MARSIS antennas unfurled. The MARSIS experiment maps the Martian subsurface structure to a depth of a few kilometres." align="left" /></a>A comment today from Mars Express Spacecraft Operations Manager Michel Denis on this week's report: "<a href="http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=49771" target="_blank">MARSIS completes measurement campaign over Martian North Pole</a>." The report gives good news! "The Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on board Mars Express has recently completed a subsurface sounding campaign over the planet's North Pole. The campaign was interrupted by the suspension of science observations several times between August and October due to safe modes and to anomalies in the operation of the spacecraft's Solid-State Mass Memory (SSMM) system. As MARSIS best observes in the dark, which for the North Pole only occurs every few years, it was among the first instruments to resume observations once a partial work-around for the problems had been implemented." In his comment below, the 'FAST Method' that Michel refers to is the operations team's newly developed way of uploading commands to Mars Express, which avoids using the problematic Solid State Mass Memory (SSMM) for critical commanding. The 'File-based Activities on Short Timeline' method essentially means that commands are grouped in very short self-contained files that can be loaded safely, in advance of execution, from the SSMM into an alternative memory unit (that is reliable but not as capacious as the SSMM). Michel writes: <blockquote> The FAST method - loading short command files upon need into the short onboard mission timeline - was put into use at the end of October 2011 with the (excellent) result that we could save what was remaining of the North Pole observation campaign by the MARSIS radar. The net loss in data collection was mitigated by using the existing MARSIS command sequences as soon as possible. Meanwhile, as for the other instruments, new MARSIS on-board control procedures (OBCPs) are under development and will allow operation with fewer commands, therefore enabling the operation of several science instruments in parallel. My main point? We did our job: contrary to widespread received wisdom, the spacecraft operators' role is not to simply watch over (supposedly) boring routine operations during the many long years of a mission - nor simply saving a spacecraft that experiences problems. In fact, we are relied upon to deliver safely as much of the expected (precious) scientific data as possible within the resources available - despite adversity. And that's what we're doing! </blockquote> General Science Operations Recovery 2011-12-16T15:19:24Z danielscuka ASPERA switch-on success :-) http://webservices.esa.int/blog/post/7/1376 This in this morning from Jonathan Schulster on the Mars Express operations team: <blockquote> The ASPERA (Energetic Neutral Atoms Analyser) instrument high voltage (kV) lines and equipment were successfully switched on today, a few minutes ago at Mars (~09:57 CET), using the new on-board control procedures (OBCP). These will run for one hour until 10:40CET today and the ASPERA science team will examine the recorded science data before giving the 'go-ahead' for full operations of ASPERA using only OBCP's starting 9 Jan uary 2012. Cheers! - Jonathan Schulster Mars Express Mission Planning & Flight Control Team </blockquote> Looks like another instrument is set to return to action! -- Daniel General Science Operations Recovery 2011-12-13T14:11:04Z danielscuka Getting Mars Express' instruments switched on http://webservices.esa.int/blog/post/7/1375 Today's update comes courtesy of Jonathan Schulster, an engineer working on the Mars Express Mission Planning & Flight Control Team. Jonathan's in the Mars Express (MEX) Dedicated Control Room at ESOC this morning, where the first commands to switch on the ASPERA (Energetic Neutral Atoms Analyser) device were sent a few minutes ago. (ASPERA is studying the interaction between the solar wind and the Martian atmosphere.) -- Daniel Jonathan writes: <img src="http://webservices.esa.int/blog/gallery/7/mex_team_in_dcr_09122011.png" align="left" />To allow the mission to restart operations of all instruments, we needed to write 'macro' on-board control procedures (OBCPs) to replace long sequences of telecommands with single 'start macro' telecommands that would fit into the restrictive memory space provided by the short mission time-line (Basically, all commands now have to be a lot shorter to be stored on board now that the solid state mass memory no longer functions properly - Ed.). The first OBCPs to switch ASPERA on and off, and its 'high voltage' lines up and down - along with on/off for PFS fourier spectrometer and the start/stop pre-heating for the OMEGA infrared (IR) spectrometer 'scanner' - were uplinked to Mars Express on Monday, 5 December. These must now be flight tested on the spacecraft. The OMEGA pre-heating test took place on 7 December during a pass over ESA's 35m ground station at Cebreros, Spain, between 08:00 08:30 GMT (09:00-09:30 CET). Today, Friday, 9 December, also between 08:00-08:30GMT, the ASPERA instrument switch on/off OBCPs were successfully flight tested. :-) <hr width="100%" size="2" /> Pierre Choukroun (Standing, Left), Erhard Rabenau (standing, right) and Jonathan Schulster, sitting, in MEX DCR this morning. <hr width="100%" size="2" />   Next week we plan to perform a full test of ASPERA with high voltage up/down after confirmation from the science team that the on/off worked fine. Regards, -- Jonathan Science Operations Recovery 2011-12-09T09:36:12Z danielscuka Mars Express steadily returns to routine operation http://webservices.esa.int/blog/post/7/1374 <a id="res_11608" href="http://webservices.esa.int/blog/gallery/7/mars_express_in_orbit_400.jpg"><img src="http://webservices.esa.int/blog/gallery/7/previews/mars_express_in_orbit_400.gif" border="0" align="left" /></a>Mission controllers are making excellent progress in returning Mars Express to routine service. Some science activities have already resumed after being temporarily suspended last month following a series of faults related to the onboard data storage system.   Having arrived around Mars in December 2003 for an initial two-year mission, the spacecraft is now in its eighth year of science operations. It has returned some of the most stunning images and valuable science data ever obtained from the Red Planet. In mid-October 2011, anomalies in the operation of its Solid-State Mass Memory (SSMM) system caused science observations to be temporarily halted. <a href="http://www.esa.int/SPECIALS/Operations/SEMYN9ZW5VG_0.html" target="_blank" title="Mars Express returns to service">Full story via ESA web</a> General Science Operations 2011-11-24T17:31:33Z danielscuka Mars Express observations temporarily suspended http://webservices.esa.int/blog/post/7/1373 Anomalies in the operation of the solid-state mass memory system on board Mars Express have caused science observations to be temporarily halted. A technical work-around is being investigated that will enable the resumption of a number of observations and should evolve into a long-term solution. In mid-August, Mars Express autonomously entered safe mode, an operational mode designed to safeguard both the spacecraft itself and its instrument payload in the event of faults or errors. The cause of entering the safe mode was a complex combination of events relating to reading from and writing to memory modules in the Solid-State Mass Memory (SSMM) system. This is used to store data acquired by the instruments and housekeeping data from the spacecraft's subsystems, prior to its transmission to Earth, and is also used to store commands for the spacecraft that have been received from the ground stations, while awaiting execution. <a href="http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=49549" target="_blank" title="ESA RSSD Site">More details in ESA's Science & Technology site</a>. General Science Operations 2011-10-31T11:36:14Z danielscuka Phobos slips past Jupiter http://webservices.esa.int/blog/post/7/1349 <a id="res_20358" href="http://webservices.esa.int/blog/gallery/7/004-2-20110610-9463-Phobos-GeomericalRelationship_H1.jpg"> <div style="text-align: center"> <img src="http://webservices.esa.int/blog/gallery/7/previews-med/004-2-20110610-9463-Phobos-GeomericalRelationship_H1.gif" border="0" alt="The trajectories of Phobos and Mars Express at the time of the conjunction with Jupiter on 1 June 2011. The graphic was created using Celestia software. The letter ‘S’ denotes the South Pole of Mars. Credit: ESA" /> </div> </a>Earlier this month, ESA’s Mars Express performed a special manoeuvre to observe an unusual alignment of Jupiter and the martian moon Phobos. The impressive images have now been processed into a movie of this rare event.   At the moment when Mars Express, Phobos, and Jupiter aligned on 1 June 2011, there was a distance of 11 389 km between the spacecraft and Phobos, and a further 529 million km to Jupiter. <a href="http://www.esa.int/SPECIALS/Operations/SEMJ53E1XOG_0.html" target="_blank">Full article via ESA</a>. General Orbits Science Operations 2011-06-17T18:44:44Z danielscuka